HOMA-IR Calculator

Estimates insulin resistance from fasting plasma glucose and fasting serum insulin using the Homeostasis Model Assessment (HOMA) equation.

Endocrinology EndocrinologyEvidence-BasedUpdated 2026-08-06

Clinical decision-support tool for qualified healthcare professionals. Results are not a diagnosis and should not replace professional clinical judgment.

Clinical Notes

HOMA-IR estimates insulin resistance from fasting plasma glucose and fasting serum insulin. In the fasting steady state, a higher insulin level relative to the accompanying glucose reflects reduced tissue responsiveness to insulin; the index expresses this relationship as (glucose × insulin) / 405, with glucose in mg/dL and insulin in µU/mL. A higher value indicates greater insulin resistance. Although a cutoff near 2.5 is often cited, there is no universally accepted diagnostic threshold, and measured values vary with the insulin assay used and with population characteristics. HOMA-IR is most useful as a tool for tracking change within the same person over time (e.g., response to lifestyle or pharmacologic interventions) rather than as a threshold-based diagnostic test. The estimate depends on a true fasting sample and a reliable insulin assay; differences in assay standardization limit comparability across laboratories and studies. It is unreliable in type 1 diabetes, in patients receiving exogenous insulin, and whenever the fasting steady-state assumption does not hold. HOMA-IR should not be used alone to diagnose diabetes or insulin resistance; it is best interpreted together with the clinical picture, glucose tolerance data, and the broader metabolic evaluation.

Calculator Information

Specialty

Endocrinology

📋 Reference Ranges

Normal Range

< 2.5

Reference ranges for this calculator
Classification	Range
Normal insulin sensitivity	<2.6
Mild insulin resistance	2.5–5
Severe insulin resistance	≥5

What This Calculator Measures

Calculates the Homeostatic Model Assessment for Insulin Resistance (HOMA-IR) to estimate insulin resistance from fasting glucose and insulin levels.

How to Use

Obtain fasting serum glucose (mg/dL) and fasting insulin (µU/mL).
Enter both values into the calculator.
Review the HOMA-IR value and interpretation.

How the Calculation Works

HOMA-IR = (fasting glucose (mg/dL) x fasting insulin (microU/mL)) / 405. Higher values indicate greater insulin resistance.

Variables Explained

Fasting Glucose

Fasting plasma glucose in mg/dL, multiplied by fasting insulin.

Fasting Insulin

Fasting serum insulin in microU/mL, multiplied by fasting glucose.

Interpretation Guide

HOMA-IR ≤2.5 is generally considered normal. Values >2.5 suggest increasing insulin resistance. Higher values indicate greater insulin resistance and metabolic risk.

Clinical Significance

HOMA-IR provides a simple, inexpensive estimate of insulin resistance that is useful in identifying patients at risk for type 2 diabetes and cardiovascular disease, and in monitoring the effectiveness of lifestyle interventions.

When It Is Useful

Research settings assessing insulin resistance
Clinical evaluation of metabolic syndrome
Monitoring response to lifestyle interventions for insulin resistance
Complementing HOMA-B to distinguish insulin resistance from beta-cell dysfunction

When It Is Not Useful

In type 1 diabetes (beta-cell destruction makes HOMA-IR unreliable)
In patients on exogenous insulin (exogenous insulin affects the calculation)
As a standalone diagnostic test for insulin resistance

Common Mistakes

Multiplying glucose in mmol/L by insulin and dividing by 405, since that constant assumes the glucose is entered in mg/dL.
Reading a result just above 2.5 as a diagnosis of insulin resistance when no universally accepted cutoff exists and assays differ between laboratories.
Calculating HOMA-IR in a patient with type 1 diabetes or on exogenous insulin, where the index is not validated and the value cannot be trusted.

Limitations

Requires fasting samples; non-fasting values are unreliable.
Less validated in certain ethnic populations and age groups.
Does not replace dynamic tests such as the hyperinsulinemic-euglycemic clamp.
Insulin assay variability between laboratories can affect results.

Worked Example

A 45-year-old woman with a family history of type 2 diabetes has a fasting glucose of 110 mg/dL and fasting insulin of 15 µU/mL.

Inputs:

glucose: 110

insulin: 15

Expected Result: HOMA-IR = (110 × 15) / (405) ≈ 4.07. This is above the normal threshold and indicates insulin resistance; evaluation for metabolic syndrome is warranted.

Evidence & References

Source:: Endocrinology / Diabetes
Reference:: Matthews DR, Hosker JP, Rudenski AS, et al. Homeostasis model assessment: insulin resistance and beta-cell function from fasting plasma glucose and insulin concentrations in man. Diabetologia. 1985;28:412-419.
Content updated:: 2026-08

Matthews DR, et al. Diabetologia. 1985;28:412-419.

References

Matthews DR, et al. Homeostasis model assessment: insulin resistance and beta-cell function from fasting plasma glucose and insulin concentrations in man. Diabetologia. 1985;28:412-419. (Original Description)

Frequently Asked Questions

What does a high HOMA-IR mean?

A HOMA-IR > 2.5 suggests insulin resistance, meaning the body's cells are not responding efficiently to insulin. This is a risk factor for type 2 diabetes, metabolic syndrome, and cardiovascular disease.

What are the units of HOMA-IR?

HOMA-IR is unitless. It is calculated using fasting glucose in mg/dL and fasting insulin in µU/mL: (glucose × insulin) / 405.

How does HOMA-IR differ from HOMA-B?

HOMA-IR estimates insulin resistance, while HOMA-B estimates pancreatic beta-cell function. Both use the same fasting glucose and insulin values but different formulas.

When should HOMA-IR be measured?

HOMA-IR requires fasting for at least 8 hours. It is best measured in the morning before any food intake.

Disclaimer: This calculator is intended for educational and research purposes only. HOMA-IR is a research and screening tool and should not be used as a standalone diagnostic test. Clinical decisions should be based on comprehensive metabolic assessment.